The effects of flooding on properties and human life has been a long standing and continuing problem, particularly in heavily populated metropolitan areas. To lessen the cost and time of recovery, recent efforts have been directed to developing barriers that can be used at the entranceway of tunnels and/or subways. It has been recognized that such barriers would also be useful in thwarting a terrorist gas attacks in such areas.
For example, as publicized in a Nov. 1, 2012 report by CNN U.S., the U.S. government is in the process of developing a huge inflatable plug which inflates like a balloon to fit the contours of a tunnel and which reportedly can reduce leakage to an amount controllable by a pump. The project has been named the “Resilient Tunnel Project.” The plug, which must be individually sized to fit a particular tunnel of particular dimension, consists of three layers, including an outer layer of thick webbing made of a liquid-crystal polymer fiber. A “typical” tunnel plug can be inflated in about three minutes and once inflated, is pressurized with either air or water. The cost of one plug is reportedly about $400,000.
While an improvement over past attempts to protect tunnels and subways from floods or threats of gas attacks, the tunnel plug is costly.
There is still a need for a versatile, portable and removable barrier for the prevention of flooding and gas attacks for tunnels, subways, and other covered structures that is also cost efficient and easily adaptable to different structures of various sizes.